An interpretation of published data on high-angle neutron elastic scattering in Tb metal

Published data of Steinsvoll et al. on high-angle elastic scattering of polarized neutrons by Tb metal are interpreted. States of the 4f-5d system at any one atomic site are assumed to be expressible as sums of products of 4f states ¦6M〉 with 5d states ¦d_M〉, where ¦6M〉 (M = 6, 5 or 4) denote 4f states with components M of their angular momenta along the b axis, and ¦d_M〉 denote 5d states which satisfy 〈d₆¦d₅〉 = β, 〈d₆¦d₄〉 = β². A small angle ? is introduced which represents an amount of tipping of the 4f moment away from the b axis which would occur if β = 1. The radii of 4f wave functions are allowed to increase by a small fraction s above values given by LS-averaged Dirac-Fock calculations. The quantities ?, βε, s and the effective polarization P of the neutron beam used are treated as adjustable parameters subject to β ? 1, and a fifth partially adjustable parameter subject to a constraint due to input information is introduced. A good fit to the results for eighteen scattering wave vectors q for which $\text{(}\text{q}\text{4π}\text{)>5nm}{}^{\mathrm{?1}}$ is obtained with ε=(10⁺⁴_?2)°, βε=(9±1)° and s=(0.018 ± 0.003).